This document specifies the minimum requirements for quality control of microbiological culture media and diluents in order to demonstrate their ability to detect microorganisms and to ensure reliability of the microbiological test methods described in the ISO cosmetics microbiology standards. This document describes mainly growth promotion and microbial control tests and is applicable to both commercially ready-to-use culture media and culture media prepared from dehydrated culture media or basic constituents in the user’s laboratory. Other methods can be substituted provided that their equivalence has been demonstrated.